Method of purifying sulphur



Patented Janall, 1927.

- UNITED- STATES PATENT oF HENRY n. WILKINSON, or BROOKLYN, 'mzw FICE.

Yonx, ASSIGNOR 'ro UNION sULPHim COMPANY, A CORPORATION OF NEW JERSEY.

mn'rrron or runrrrmo SULPHUR.

Nb Drawing.

Sulphur obtained by methods involving melting of the sulphur underground and raising the same to the surface by means of superheatedwater, is of sufficient purity for many commercial purposes, buthowever, lacks the bright yellow color and brilliant appearance demandedof the more highly purified product. It contains noticeable amounts ofpetroleum-like matter and oceluded gases, as well as water, and in aform v in this condition removable with for agricultural and otherpurposes, there are many applications of sulphur where a purer productis required, and the process as described in the present specificationis designed to give such a; product.

Some of the processes for the manufacture of flowers of sulphur whichhave been described, concern themselves with methods vided solid.

of operation involving either reduced pressure or the use of inert gasesfor preventing combustion of the sulp in this art that the danger fromcombustion of the very finely divided sulphur is great, andthis dangermay be minimized or avoided by the use of inert ases, or by carrying outthe production of owers of sulphur in a partial or substantiallyabsolute vacuum.

It has now been found in the further development of these processes thatthe production of finely divided, sulphur may be tures than that of thenormal atmospheric boiling point of sulphur, and considerably lower thanthe boiling point of the sulphur under the conditions prevaling in theapparatus, by so conducting the operation that the sulphur is virtuallyevaporated without actual ebullition. I I

To make this clearer, left .it be. assumed that sulphur will boil at 350C. under a vacuum of 24 inches, theniatthat temperature sulphur vaporwould be produced, and

" as such may becondensed either to a liquid or to a finely divided themeans employed. of a current of inert gas, such as carbon dioxide,nitrogen or'flue gas, the sulphur may be carried-into a relatively smallcondensing .chamber, and there collected as a finely diso1id,- dependingupon By the employment The present process difl'ers from hose processeswhich (have preceded it in this essential, that the sulphur is vaporizedat difficulty. While suitable b found that considerable hur. It isrecognized a 'which. may or. may not be the Application filed November26, 1923. Serial No. 677,184.

a temperature consierably below its boiling point. Forexample, under-theconditions above outlined, the sulphur is vaporized at temperaturesbetween 275 and 300 C. In order to obtain this effect, sential toconduct a diluent or carrying medlum, such as a gas or vapor, beneaththe surface of the sulphur so heated. In order to prevent'combustion, anon-oxidizing and inert gas such as nitrogen, flue-gas or caron dioxideshould be employed. V

This process may also be carried out at atmospheric pressure byforcingsuch as gas under the surface of sulphur heated to liquefaction,and conducting the gas carrying sul- 0 phur into a suitable condensingor collecting chamber. At atmospheric pressure, sulphur boils at or near444 0., but I have amounts of sulphur may be evaporated and convertedintoa very finely divided and highly purified condition by heatingsulphur in a suitable vessel to a temperature of between 300350 (3.,then passing an inert gas into and under the surface of the heatedsulphur, so thatsaid gas will pass through the heated sulphur in astream of smallbubbles. This gas will absorb heat from the sulphur, butmay be heated by outside means to even a higher temperature than that towhich the sulphur itself has been heated. This gas, passing through themolten sulphur, will cause an evaporative effect to be applied to thesulphur, and a portion of the sulphur will be carried along by such gasin the form of diluted sulphur vapor and into a chamber connected withthe primary heating vessel or retort. I have also found it tobeadvantageous to further dilute the sulphur-bearing gas with furtherquantities of an inert gas, same kind of gas which is carrying thesulphur. Under certain conditions, I have/successfully employed air forthe purpose of producing a 100 chilling effect, thereby preventing orretarding the agglomeration of the particles of sulphur, which may ormay not exhibit thermoplasticity. I

The gas carrying the sulphur isconducted 105 to a suitable collectingchamber, and the gas, in order to remove any entrained sulphur therein,may be bubbled through water orother liquid, and re-used by introductioninto more molten sulphur as before de- 0 however, it is cs '0 a scribed,

,\ method is carried out,

ratio in the prod the circulation being effected or maintained by eithera pump, fan or other means for producing a circulation of the same.

The lower the temperature at which this the larger will be the uctoithat form of sulphur soluble in carbon bisulphide, and thus a means ishereby provided for regulating the amount in the product, of that termof sulphur insoluble in carbon bisulphide. This is an importantconsideration, as commercial flowers of sulphur as usually produced, ishigh in ercentage in that form ofsulphur insolu le in carbon bisulphide.

Having therefore described my method, and the means whereby it may beefiectuated, what I claim as new and desire to secureby patentapplication is 1. A method of producing finely divided sulphur,consisting in heating sulphur until molten but at a temperature belowits boiling point under the conditions of heating,

passing into and through said molten sulphur a current of gas,transferring said gas to a collecting chamber, allowing said gas todeposit sulphur in said chamber, purifying said gas, and re-introducingsaid purified gas into more molten sulphur, substantially as described.

2. A method of producing finely divided sulphur consisting in heatingsulphur until molten .l

but at a temperature below its boiloint under the conditions of heating,passing into and through said molten sulphur a current of gas incapableof supporting combustion, transferring said incombustible gas to acollecting chamber, allowing said gas to deposit sulphur in saidchamber,

purifying said gas, and re-introducing said purifiedgas into more moltensulphur, substantially as described.

3. A method for the purification of sulphur by vaporization attemperatures below the boiling point of the sulphur under the conditionsof treatment, characterized by passing a gas inert to the sulphurthrough sulphur,

, sulphur,

and twenty-three.

and into said sulphur while in the molten condition, afterwardstransferring said gas.

into a chamber suitable for the deposition of allowing said sulphur todeposit in said chamber, purifying said gas and re-int-roducing thepurified gas into more molten sulphur, substantially as described.

4. A method for the purification of sulphur by vaporization attemperatures below the boiling point of the sulphur under the conditionsof treatment, characterized by passing an inert gas intoand through saidsulphur while the sulphur is in a molten condition, afterwardstransferring said gas into a chamber suitable for the deposition ofsulphur, allowing the sulphur to deposit from the gas in said chamber,then puritying said gas and re-introducing the purified gas into moremolten sulphur, substantially as described,

5. A process for transferring sulphur from a retort wherein it is meltedat a temperature below its boiling point, by passing into and throughsaid heated sulphur a current of gas incapable of supporting combustion,said gas carrying sulphur being then led into a cooling or condensingchamber for the deposition therein of the sulphur carried by said gas,purifying the gas from the sulphur remaining therein and therewith, andreturning said gas through the system for re-use by passing into andunder more molten sulphur, substantially as described.

6. A method of producing finely divided consisting in heating sulphurunder conditions which will cause it to melt at a temperature below itsboiling point, passing through the molten sulphur a current or inertgas, and transferring-the gas and sulphur carried thereby into acondensing chamber. 7

Signed at vBrooklyn, in the county of Kings, and State of New York, thistwentysecond day of November,

HENRY H. WILKINSON.

nineteen hundred

